Why Women Outlive Men

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Women have outlived men for years, and an Australian-led research team says the reason why is all in the genes.

Mutations to the DNA of cell mitochondria can account for differences in the life expectancy of males and females—namely how long males live, and the speed at which they age, the team concluded. In research published in Current Biology, the team found that genetic variation across mitochondria were reliable predictors of life expectancy in male fruit flies (Drosophila melanogaster), but not in female fruit flies.

“Ultimately, this evolutionary process could result in the evolution of male-specific mitochondrial mutation loads, an idea previously termed Mother's Curse,” concluded the team. “The effects of this process are broader than hitherto realized, and that it has resulted in mutation loads affecting patterns of aging in male, but not female, Drosophila melanogaster.”

Corresponding author Damian Dowling, Ph.D., led the team, which included Ph.D. student Florencia Camus, both from Monash University’s School of Biological Sciences; and David Clancy, Ph.D. of Lancaster University in the UK.

“The tendency for females to outlive males is common to many different species. Our results therefore suggest that the mitochondrial mutations we have uncovered will generally cause faster male aging across the animal kingdom," Dr. Dowling said in a statement.

He noted that while children receive copies of most of their genes from both their mothers and fathers, they only receive mitochondrial genes from their mothers.

“If a mitochondrial mutation occurs that harms fathers, but has no effect on mothers, this mutation will slip through the gaze of natural selection, unnoticed. Over thousands of generations, many such mutations have accumulated that harm only males, while leaving females unscathed," Dr. Dowling added. “What we seek to do now is investigate the genetic mechanisms that males might arm themselves with to nullify the effects of these harmful mutations and remain healthy.”